This application claims the benefits of Japanese Applications No. 2000-029283 and No. 2000-398959 which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a one-way clutch device for constituting an automatic transmission, or the like, for a car, and more specifically, to the technology for achieving appropriate lubrication, or the like, in sliding parts.
2. Related Background Art
Generally, an automatic transmission for a car is provided with a sun and planet gear mechanism of three to five speed levels, in addition to a torque converter serving as a fluid coupling, so as to change the speed by properly fixing or releasing constituent elements (such as a sun gear or a planet gear) of the sun and planet gear mechanism by means of frictional engagement means such as a clutch or a brake. As the frictional engagement means to be assembled in an automatic transmission, there is employed a wet-type multiple disc means in which friction plates and separator plates are alternately arranged, except in a specific type of a band brake, and the pressure oil supplied from a transmission control oil pressure circuit is used for the pressure contact (frictional engagement) between the both plates. Some of such frictional engagement means employ a structure in which a one-way clutch device is assembled therein, and a gear shaft, and the like, are freely rotated in one direction of rotation, thereby facilitating the transmission control.
FIG. 16 shows a longitudinal cross section of a conventional one-way clutch device which is incorporated in the frictional engagement means. Such one-way clutch device 1 is composed of an inner race 5 which is formed with an oil path 31 to be open on the outer peripheral surface thereof, an outer race 9 which is supported to be coaxial and to be rotatable relatively with this inner race 5, a one-way clutch mechanism 51 interposed between the inner race 5 and the outer race 9, etc. The one-way clutch mechanism 51 is composed of a large number of sprags 55 serving as torque transmitting members, ribbon springs 57 for retaining and, at the same time, for biasing the sprag 55 in the direction of engagement, an outer retainer 59 for retaining the ribbon springs 57 annularly, an inner retainer 61 for suppressing an excessive inclination of each sprag 55 together with the outer retainer 59, a pair of end bearings 63 for retaining the both retainers 59 and 61 with a predetermined gap therebetween so as to secure an operation of the sprag 55, and a synthetic resin washer 64 which is in a sliding contact with the outer side surface of the left end bearing 63 shown in FIG. 16.
In this one-way clutch device 1, while the inner race 5 is fixed, the outer race 9 is rotated, whereby the one-way clutch mechanism 51 is rotated together with the outer race. In FIG. 16, the member denoted by reference numeral 65 is a snap ring, the member denoted by reference numeral 67 is a latching plate which is fixed by the snap ring 69. Both members are adapted to restrict a movement of the one-way clutch mechanism 51 in the axial direction.
In the one-way clutch device 1 described above, since the inner race 5 is fixed, the lubrication using the centrifugal force can not be conducted, so that lubricating oil is sent with pressure to the oil path 31 of the inner race 5 by a forcible lubrication means such as an oil pressure pump. As indicated by the arrow in FIG. 16, the lubricating oil supplied from the inner peripheral side of the inner race 5 flows into the inner peripheral side of the sprag 55 through the oil path 31 and then flows out from gaps between the end bearing 63, the snap ring, and a side plate 65 and the inner race 5. Then, since the sprag 55 and the end bearing 63 are rotated integrally with the outer race 9, the sliding surfaces between these members and the inner race 5 are lubricated by the supplied lubricating oil. However, an opening portion of the oil path 31 is formed on the outer peripheral surface of the inner race 5 which is in sliding contact with the sprag 55. Thus, there arises a problem that a surface pressure generated in the sprag 55 partially increases when the torque is transmitted (when the one-way clutch mechanism 51 is operated).
On the other hand, in the one-way clutch device described above, since the torque transmitting members (sprags) rotating with the outer race are brought into sliding contact with the outer peripheral surface of the inner race, the lubrication described above can be conducted in the manner as described above even if the inner race is an element on the fixed side. However, when the torque transmitting members (such as steel balls) serve as elements on the fixed side together with the inner race, the lubricating oil hardly reaches a sliding surface between the outer race and the torque transmitting member, so that the lubrication between the inner peripheral surface of the rotating outer race and the torque transmitting members can not be conducted smoothly. Particularly, when there is a small gap between the one-way clutch mechanism and the surrounding members, it is very difficult to secure an oil path for supplying the lubricating oil in a required amount to the sliding surfaces.
The present invention has been contrived to take the above circumstances into consideration, and an object thereof is to provide a one-way clutch for providing appropriate lubrication for sliding portions.
In order to solve the above problems, according to a primary aspect of the invention, there is provided a one-way clutch device comprising a plurality of torque transmitting members interposed between an inner race and an outer race for transmitting a rotating force between the inner race and the outer race through the torque transmitting members only in one direction of rotation, in which a side part of the inner race is formed with a plurality of oil paths for supplying the lubricating oil. According to this one-way clutch of the primary aspect of the invention, since no lubricating oil outflow port, or the like, is formed on the inner race, the lubricating oil is supplied without increase of the surface pressure of the torque transmitting member.
Also according to a second aspect of the invention in the one-way clutch device of the primary aspect, an annular member may be provided to face the inner race and the torque transmitting members to be fixed with respect to the inner race and the torque transmitting members, and the oil paths are formed through the annular member. According to this feature of the second aspect of the present invention, the lubricating oil passing through the oil paths reaches the inner peripheral side of the outer race since, for example, the oil paths are formed to be extended to the outer side of the torque transmitting members.
Also according to a third aspect of the present invention, in the one-way clutch device of the primary aspect of the present invention, an annular member may be formed to face the inner race and the torque transmitting members to be fixed with respect to the inner race and the torque transmitting members, and the oil paths are formed between the torque transmitting members and the annular member.
According to the third aspect of this invention, the oil paths can be formed comparatively easily to easily cope with a change of the form of the oil paths.
Also, according to a fourth aspect of the present invention, the one-way clutch device of the primary aspect of the present invention may be provided with an annular member which is provided to face the inner race and the torque transmitting members to be fixed with respect to the inner race and the torque transmitting members and a latching plate which is rotated relatively to the annular member together with the outer race, wherein the oil paths are formed on the annular member to be open to the latching plate. According to the fourth aspect of the present invention, when the annular member and the latching plate are rotated relatively to each other, the lubricating oil flowing into the oil paths is guided to the outer peripheral direction by the centrifugal force, and this lubricating oil generates an action for separating the annular member from the latching plate to thereby decrease the dragging torque.
Also according to a fifth aspect of the present invention, in the one-way clutch device of the fourth aspect, the annular member may be provided with a communication oil path for communicating the oil paths with the surface on which the torque transmitting members are formed.
According to the fifth aspect of the present invention, the lubricating oil which is guided through the oil paths in the outer peripheral direction by the centrifugal force is supplied to the torque transmitting members, and the like, through the communication oil path.
Also according a sixth aspect of the present invention, in the one-way clutch device of the second to fifth aspect, the annular member may be a retainer made of synthetic resin. According to this sixth aspect, it is possible to form the oil paths comparatively easily, and to cope with a change of the form of the oil paths easily.
Also according to a seventh aspect of the present invention, in the one-way clutch device of the sixth aspect, the oil path may be a communication hole formed in a flange portion of the retainer. According to this feature of the seventh aspect, the lubricating oil may be directly supplied to the sliding surface of the torque transmitting member or the bearing member required to be lubricated.
Also according to an eighth aspect of the present invention, in the one-way clutch device of the primary to seventh aspect, a lubricating oil outflow port of the oil path may be provided to be adjacent to at least one of the torque transmitting member and the bearing member. According to this feature of the eighth aspect, the lubricating oil is directly supplied to the sliding surface of the torque transmitting member or the bearing member required to be lubricated.
Also according to a ninth aspect of the present invention, in the one-way clutch device of the sixth aspect, the oil path may be a groove which is formed in the flange portion of the retainer. According to this feature of the ninth aspect, it is possible to form the oil path comparatively easily, and to cope with a change of the form of the oil path easily.
Also according to a tenth aspect of the present invention, in the one-way clutch device of the primary to ninth aspect, the lubricating oil inflow port may be stretched toward the opening end thereof. According to this feature of the tenth aspect, the lubricating oil is taken into the oil paths with efficiency.
Also according to an eleventh aspect of the present invention, in the one-way clutch device of the primary to tenth aspect, the lubricating oil inflow ports of the oil paths may be communicated with each other. According to this feature of the eleventh aspect, the lubricating oil is taken into the oil paths with efficiency.
Also according to an twelfth aspect of the present invention, in the one-way clutch device of the primary to eleventh aspect, the each of the lubricating oil outflow ports of the oil paths may be open toward at least one sliding surface of the torque transmitting member or the bearing member. According to this feature of the twelfth aspect, the lubricating oil is directly supplied to the sliding surface of the torque transmitting member or the bearing member required to be lubricated.
Also according to a thirteenth aspect of the present invention, in the one-way clutch device of the twelfth aspect, each of the lubricating outflow ports may have a step portion. According to this feature of the thirteenth aspect, the lubricating oil is directly supplied to the sliding surface of the torque transmitting member or the bearing member required to be lubricated.
Also according to a fourteenth aspect of the present invention, in the one-way clutch device of the primary to thirteenth aspect, the inner race may have a cam surface on the outer peripheral surface thereof and the torque transmitting members may be interposed between the cam surface of the inner race and the outer peripheral surface of the outer race; and the one-way clutch device may further comprise a biasing means for biasing the torque transmitting members in the direction of engagement, a block bearing for forming a predetermined gap between the inner race and the outer race, and a retainer for retaining the torque transmitting members, the biasing means and the block bearing.
Also according to a fifteenth aspect of the present invention, in the one-way clutch device of the primary to the fourteenth aspect, the inner race may be an element on the fixed side and the outer race may be an element on the rotating side.